Leg muscles motion during whole body linear frequency sweep vibration

A. Fratini*, A. la Gatta, P. Bifulco, M. Cesarelli, G. Pasquariello

*Corresponding author for this work

Research output: Chapter in Book/Published conference outputConference publication


Whole body vibration (WBV) aims to mechanically activate muscles by eliciting stretch reflexes. Mechanical vibrations are usually transmitted to the patient body standing on a oscillating plate. WBV is now more and more utilized not only for fitness but also in physical therapy, rehabilitation and in sport medicine. Effects depend on intensity, direction and frequency of vibration; however, the training frequency is one of the most important factors involved. A preliminary vibratory session can be dedicated to find the best vibration frequency for each subject by varying, stepwise, the stimulation frequency and analyzing the resulting EMG activity. This study concentrates on the analysis of muscle motion in response to a vibration frequency sweep, while subjects held two different postures. The frequency of a vibrating platform was increased linearly from 10 to 60 Hz in 26 s, while platform and single muscles (Rectus Femoris, Biceps Femoris - long head and Gastrocnemius Lateralis) motions were monitored using tiny, lightweight three-axial MEMS accelerometers. Displacements were estimated integrating twice the acceleration data after gravity contribution removal. Mechanical frequency response (amplitude and phase) of the mechanical chains ending at the single muscles was characterized. Results revealed a mechanical resonant-like behavior at some muscles, very similar to a second-order system in the frequency interval explored; resonance frequencies and dumping factors depended on subject and its positioning onto the vibrating platform. Stimulation at the resonant frequency maximizes muscle lengthening, and in turn muscle spindle solicitation, which produce muscle activation.

Original languageEnglish
Title of host publicationWorld Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany
Subtitle of host publicationVol. 25/9 Neuroengineering, neural systems, rehabilitation and prosthetics
EditorsOlaf Dössel, Wolfgang C. Schlegel
Place of PublicationBerlin (DE)
Number of pages4
ISBN (Electronic)978-3-642-03889-1
ISBN (Print)978-3-642-03888-4
Publication statusPublished - 2009
EventWorld Congress on Medical Physics and Biomedical Engineering - Munich, Germany
Duration: 7 Sept 200912 Sept 2009

Publication series

NameIFMBE proceedings
ISSN (Print)1680-0737


CongressWorld Congress on Medical Physics and Biomedical Engineering
OtherImage Processing, Biosignal Processing, Modelling and Simulation, Biomechanics


  • Frequency response
  • Muscle motion
  • Whole body vibration


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